Re: How to do count for sub list?????

• To: mathgroup at smc.vnet.net
• Subject: [mg82192] Re: How to do count for sub list?????
• From: Jean-Marc Gulliet <jeanmarc.gulliet at gmail.com>
• Date: Sun, 14 Oct 2007 06:15:01 -0400 (EDT)
• Organization: The Open University, Milton Keynes, UK
• References: <fen5rk\$4gi\$1@smc.vnet.net>

```wangzhen0829 at gmail.com wrote:

> I am new to Mathematica, and now I have a problem with it, hope to get
> some help from here.
>
> I have a
>
> {{0, 0, 0, 0, 0, 0, 0, 0, 0, 0}, {0, 0, 0, 0, 0, 0, 0, 0, 0, 0}, {
>   0, 0, 0, 1, 0, 0, 0, 0, 0, 1}, {1, 0, 0, 0, 0, 0, 0, 0, 0, 0}, {
>   0, 0, 0, 0, 0, 0, 0, 0, 0, 0}, {0, 0, 0, 0, 0, 0, 0, 0, 0, 0}, {
>   0, 0, 0, 0, 0, 0, 0, 0, 1, 0}, {0, 0, 0, 0, 1, 0, 0, 0, 0, 0}}
>
> I need to get a list which represent the number of NON-zero number in
> each sublist.
>
> I should get a list like:
>
> {0,0,1,1,0,0,1,1}
-------^
I believe that the third entry should be a two rather than a one.

Assuming that you want to count the numbers of ones within each
sublists, you could use, among many other way, one of the following:

In[1]:= lst = {{0, 0, 0, 0, 0, 0, 0, 0, 0, 0}, {0, 0, 0, 0, 0, 0, 0,
0, 0, 0}, {0, 0, 0, 1, 0, 0, 0, 0, 0, 1}, {1, 0, 0, 0, 0, 0, 0, 0,
0, 0}, {0, 0, 0, 0, 0, 0, 0, 0, 0, 0}, {0, 0, 0, 0, 0, 0, 0, 0,
0, 0}, {0, 0, 0, 0, 0, 0, 0, 0, 1, 0}, {0, 0, 0, 0, 1, 0, 0, 0, 0,
0}};

Count[#, 1] & /@ lst

Total[Transpose@lst]

Plus @@@ lst

Out[2]= {0, 0, 2, 1, 0, 0, 1, 1}

Out[3]= {0, 0, 2, 1, 0, 0, 1, 1}

Out[4]= {0, 0, 2, 1, 0, 0, 1, 1}

Regards,
--
Jean-Marc

```

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